The present invention relates to a camera system having a function of monitoring a plurality of view angles and positions and detecting an abnormal entrance from monitored images.
A surveillance camera with a fixed monitor position for detecting an abnormal entrance by an image A recognition process is disclosed in JP-A-9-276237. This monitor camera always takes an image at a fixed monitor position and any change in the image is checked by the image recognition process to detect an abnormal entrance.
Another surveillance camera mounted with a pan/tilt driver unit and a preset unit is disclosed in JP-A-8-139987. This camera is set to take an image at a desired position, and pan, tilt, zoom and focus positions for that position are preset to control the camera monitor position in accordance with the preset values. An image recognition method is not disclosed in this publication.
There is a high demand that a single camera automatically recognizes and watching a plurality of monitor positions and view angles. For automatic recognition of a monitor object, a recognition camera utilizing an image recognition process is known. However, a single focus and fixed view angle camera capable of automatically monitoring a plurality of different view angles and positions is not known.
Products of a combination of a tripod head capable of panning and tilting and a zoom camera for monitoring a plurality of view angles and positions are known. However, although most of these products preset monitor positions and angle views to switch therebetween at high speed and monitor a wide image area, they cannot perform automatic recognition of a monitor object because an image recognition process is not incorporated.
Even if these two kinds of techniques are combined, image recognition may become unstable each time switching occurs among a plurality of view angles and positions. Erroneous recognition may occur and an abnormal entrance cannot be detected reliably.
It is an object of the present invention to provide a multi-point surveillance camera system capable of obtaining an optimum image recognition result and reliably detecting an abnormal entrance even if the camera is moved to a different preset position or view angle.
In order to achieve the above object of the invention, a combination of an image recognition unit a zoom camera equipped with a pan/tilt driver unit for changing a camera monitor position is used to monitor a plurality of monitor positions. The monitor position is changed by using the pan/tilt unit, and an image recognition unit starts an image recognition process to reliably detect an abnormal entrance at the plurality of monitor positions, after a focus position adjustment by preset information (after completion of commanding to change the focus position to a preset position or stop at the preset position), after an automatic focusing operation (herein-after called an AF operation), or after a combination of the focus position adjustment by the preset information and the automatic focusing operation.
According to another aspect of the invention, a combination of an image recognition unit a zoom camera equipped with a zoom mechanism for changing a camera monitor view angle is used to monitor a plurality of monitor positions, at least two monitor positions having different view angles. The camera monitor view angle is changed in accordance with preset information, and an image recognition unit starts an image recognition process to reliably detect an abnormal entrance at the plurality of monitor positions, after completion of changing to the present position or completion of an operation by the zoom mechanism, after completion of setting an in-focus state by the automatic focusing operation, or after a combination of the focus position adjustment by the preset information and the automatic focusing operation.
According to the invention, the image recognition unit starts the image recognition process after the automatic focusing operation, at the same time when the automatic focusing operation starts, a timer is activated, if the in-focus state does not enter in a predetermined time lapse, the focus position is forcibly set to the preset position, and thereafter the image recognition unit starts the image recognition process to reliably detect an abnormal entrance at a plurality of monitor positions.